Shiva Purana
नन्दीश्वर उवाच ॥ इत्युक्त्वा तं शिवा देवी शिवतत्त्वं जगाद सा ॥ यत्र ब्रह्मतया रुद्रः कथ्यते निर्गुणोऽव्ययः ॥ ४५॥
Nandīśvara said:— After saying this, Pārvatī expatiated on Śiva’s principle, where Śiva was explained as attributeless and unchanging performing the penance of Brahman.
english translation
nandIzvara uvAca ॥ ityuktvA taM zivA devI zivatattvaM jagAda sA ॥ yatra brahmatayA rudraH kathyate nirguNo'vyayaH ॥ 45॥
hk transliteration by Sanscript